This invention relates to new chemical compounds which have value in the field of medical science. More particularly, it relates to new chemical compounds which are of value for administration to a mammalian subject, particularly man, as immunosuppressive agents. These new immunosuppressive agents can be compared to the macrolides known as FK-506 and FK-520, which are described in further detail in U.S. Pat. No. 4,894,366. The new compounds of this invention will find especial utility in preventing or treating graft rejection following skin or organ transplant surgery and in preventing or treating autoimmune diseases such as rheumatoid arthritis and psoriasis. Additionally, these macrolide derivatives will find use in preventing or treating infectious diseases caused by fungi.
Graft or organ transplant rejection following transplant surgery is a common occurrence which arises when foreign antigens are recognized by the host's immune response system. The host's immune response system, in an effort to "protect" itself from the foreign tissue, then releases its cellular and humoral arsenal. Both activated lymphocytes and antibodies attack the foreign tissue, resulting in complications which often end in rejection of said tissue.
Similarly, the occurrence of immunoregulatory irregularities in autoimmune and chronic inflammatory diseases is well known. Irrespective of the underlying etiology of the condition, a variety of autoantibodies and self-reactive lymphocytes often arise to complicate the condition.
Treatments which target the immune response system often result in a complete shutdown of the system, leading to a lowering of the body's ability to combat infection. This can be as dangerous as the original condition which led to the shutdown.
Currently the leading medicinal agent for the prevention or treatment of graft rejection is cyclosporin A, approved by the United States Food and Drug Administration in 1983. The drug acts by inhibiting the body's immune response system from mobilizing its arsenal of natural protecting agents to reject the transplant's foreign protein. Although cyclosporin is effective in fighting graft rejection, it suffers drawbacks in that it can cause kidney failure, liver damage and ulcers; which in many cases can be very severe. Safer drugs which are more selective in their ability to affect the immune response system and which have fewer side effects are constantly being pursued.
U.S. Pat. No. 4,894,366 discloses the macrolides FK-506 and FK-520, inter alia, as immunosuppressants, including the treatment of "resistance to transplantation," autoimmune diseases and infectious diseases. International Patent Publication No. WO 91/02736 discloses derivatives of FK-506, FK-520 and related macrolides. European Patent Publication No. 428,365 A1 discloses various other derivatives of FK-506, FK-520 and related macrolides.